Solar technologies harness solar energy, which is free and unlimited. They are broadly characterised as either passive or active, depending on the way they capture, convert and distribute solar energy. Active solar techniques are based on photovoltaic panels and solar thermal collectors. Passive solar techniques include orienting a building to the sun, selecting materials with favourable thermal mass or light dispersing properties and designing spaces that naturally circulate air.

However, solar-power stations can be rather extensive. Alexander Mitsos and Corey Noone, two researchers from the Massachusetts Institute of Technology, have now thought up a more efficient way to build arrays of mirrors occupying almost 16% less space.

The mirrors are normally placed in concentric semicircles facing a tower, on top of which there are the boiler and turbine: they sometimes shade each other as the sun moves. The researchers divided each of the mirrors in a real power plant, PS10, in southern Spain into about 100 pieces and calculated all the energy losses using a computer model. It resulted that the more compact and efficient pattern is a Fermat spiral, a design where each element is set at a constant angle of 137° to the previous one, which is exactly the arrangement of the florets of a sunflower!

If you are interested in clean energies, you may also like Deep Heat.